Connective Tissues Flashcards

Connective Tissues

Connective tissue is one of the four main types of tissues in the body, along with nervous, muscle, and epithelial tissue.

Types of Connective Tissues

Connective tissues include:

  • Bone
  • Cartilage
  • Blood

Functions of Connective Tissues

  • Provide support and bind other tissues together.
  • Provide insulation and protection for other tissues.
  • Transport substances.

General Characteristics of Connective Tissues

  • All connective tissues originate from mesenchyme stem cells.
  • Vary in vascularity (presence of blood vessels).
  • Composed mainly of extracellular matrix.

Extracellular Matrix

The extracellular matrix is a major component of connective tissue and consists of:

  • Ground substance: Watery or gel-like substance secreted by cells.
  • Fibers or Threads:
    • Collagen
    • Elastic
    • Reticular

Loose Connective Tissue

Types of loose connective tissue:

  • Areolar
  • Adipose
  • Reticular

Areolar Connective Tissue

  • Mostly open space.
  • Holds water and salts for surrounding tissues.
  • Found under epithelium and around organs.

Adipose Connective Tissue

  • Composed of fat cells (adipocytes).
  • Adipocytes have large vacuoles that contain fat/oil.
  • Insulates and warms the body.
  • Provides nutrients to other cells.

Reticular Connective Tissue

  • Contains reticular fibers, which create a stiff framework.
  • Supports other cells.

Dense Connective Tissue

Types of dense connective tissue:

  • Regular
  • Irregular
  • Elastic

Regular Dense Connective Tissue

  • Collagen fibers are arranged in one direction.
  • Provides tensile strength, like a rope.
  • Found in tendons and ligaments.

Irregular Dense Connective Tissue

  • Collagen fibers are arranged in many directions.
  • Provides strength in multiple directions.
  • Found in capsules around organs.

Elastic Dense Connective Tissue

  • Provides flexible cushioning.
  • Found between vertebrae and in arteries.

Cartilage

  • Avascular and lacks nerves

Types of cartilage:

  • Hyaline
  • Fibrocartilage
  • Elastic

Hyaline Cartilage

  • Glassy looking.
  • Firm ground substance with lacunae (spaces for cells).
  • Few collagen fibers.
  • Found in the larynx, bridge of nose, and ribs.

Fibrocartilage

  • Contains lots of collagen, mostly running parallel.
  • Found in intervertebral discs.

Elastic Cartilage

  • Highly flexible.
  • More elastic fibers.
  • Found in the outer ear and tip of nose.

Bone

  • Calcified ground substance

Types of Bone:

  • Spongy
  • Compact

Bone Formation

  • Osteocytes secrete ground substance, fibers, collagen, and fluids.
  • The ground substance eventually becomes calcified and hard.

Blood

  • Vascular tissue with a connective tissue nature.

Components of Blood

  • Ground substance = plasma (fluid).
  • Fibers = platelets, which clot the blood.

Cells in Connective Tissue

  • Mast Cells
  • Macrophages
  • Blood Cells

Mast cells

  • Detect foreign substances.
  • Contain granules that secrete inflammatory chemicals.

Macrophages

  • Blob-like cells that engulf invading substances or organisms.

Blood Cells

  • Red Blood Cells (erythrocytes): carry oxygen.
  • White Blood Cells (leukocytes): provide immune response.

Ground Substance Variation

  • Connective tissues can have different types of ground substances in the extracellular matrix.
  • Cartilage has a flexible ground substance.
  • Bone has a calcified ground substance.
  • Blood has a fluid ground substance.